Investigation of the efficacy of BDOC protocols used in biofilm measurement and monitoring

Abstract

Access to good quality drinking water is essential for the maintenance of public health. To guarantee a steady supply of good quality water, water treatments plants are designed to provide potable water that meets national and, where necessary, local water quality standards. While the protection of natural water resources against pollution, and proper treatment of water at treatment plants are both crucial to the provision of safe drinking water, the reality is that the quality of treated water can degrade during distribution. Microbial proliferation within distribution systems can cause problems such as unpleasant tastes and odours as well as the proliferation of pathogenic microorganisms. For most utilities, it is biofilm that grows on pipe surfaces that act as permanent inocula continuously inoculating the bulk water as it flows through the distribution system. Distribution system biofilm growth and the resulting impact on water quality can be minimized by various treatment processes, designed to remove biodegradable organic matter (BOM) from the water. The removal of BOM is of great importance to water utilities because it eliminates bacterial regrowth and the many associated water quality issues. Hence, the spatial and temporal mapping of biodegradable organic carbon (BDOC) offers water utilities an effective strategy in managing the BOM in the distribution system. This research is aimed at evaluating the applicability of BOM measurement protocols to monitoring biostability and biofilm formation potential within a drinking water distribution system (DWDS). This study specifically investigated the efficacy of a simplified version of the high-density BDOC test as a protocol for monitoring BDOC in finished water. The high-density BDOC protocol was found to be a more streamlined approach in contrast to the assimilable organic carbon (AOC), and provides a suitable monitoring mechanism for lowering biofilm formation potential in DWDSs.